The invention generally relates to wireless networks, and more specifically to mobile video delivery.
In general, progressive download refers to video delivered by a regular Hypertext Transfer Protocol (HTTP) web server rather than a streaming server. In most instances, video delivered using this technique is stored on a viewer's hard drive as it's received, and then it's played from the hard drive. In contrast, streaming video is usually not stored (also called cached) locally, so if the viewer can't retrieve and play it in real time, he or she can't play it smoothly at all.
HTTP Progressive download is the most common mode of delivering video from the Internet today. Unfortunately, this delivery method does not respond to changing network conditions, which can affect the end user experience. Consider a case where a HTTP PD video object is encoded at 720p. If the network conditions are bad, the video will take a long time to be downloaded and video player will stall waiting for additional frames. For such conditions, the object has to be encoded at a lower rate (perhaps 360p). Similarly, if the network conditions improve, the streamer has to start sending higher quality video segments.